Well say I'm getting old ( and sensible?) but I've alway been a victim of the grass is always greener when it comes to bike ownership!
I think many people buy, thinking they will be faster on a newer bigger HP bike. But the bike is largely irrelevant, and you may not be quicker, happier or more impressed with a new bike unless it is vastly different, and to be used for a different purpose than the previous.
While I had an Aprila RSVR prior to the SD, the duke is so much more fun and comfortable which I like and am happy with it.
If I were to trade it on a Tuono, or jap naked, I would be no faster and probably no happier! I love the SD, it ticks all the boxes as an underdog. Not being over powered means you can wring it's neck, ride it to it's limits and get that pump from getting the best from it. Quite frankly, if you need more it should be on the track!
I have a track bike for that purpose.
On the road the SD is the ultimate for me, a hooligan bike with attitude, capable of embaressing any other road bike in the right hands.
So weigh up carefully before changing. A well sorted SD that you know, and have spend your hard earned cash on. to get it to that point where you trust it,rely on and love it........well say no more!
Best of luck with your descision.